Ploughing systems or for agricultural work using harrows, make a cut on the vegetable matter that may be on the surface of the land, achieving a shredded of that vegetable matter that allows leaving the land in optimal conditions, or at least suitable for carrying out the seeding.
The invention is intended for application in disc harrows, and in particular for carrying out coupling of the disc to the hub corresponding to the frame of the harrow.
As is known, disc harrows are formed by a plurality of discs with the shape of spherical cap rotating about respective hubs attached to the frame of the harrow, which hubs normally form certain angle with the forward direction, besides being inclined with respect to the horizontal plane that obviously corresponds to the land plane, all so that the land cut by each disc in the rotation thereof exerts pressure against the disc itself and makes it rotate.
As mentioned in the preceding paragraph, each disc will be related to a corresponding hub, which means that it is necessary to mount one by one the different discs on the corresponding hubs of the frame to form the harrow. Said assembly and/or disassembly operation, is laborious and there is no known system for a quick change of the discs in their hubs.
Conventionally, the way of centering and coupling each disk to its respective hub is based on the fact that it has a sort of concentric cylindrical neck emerging frontally, which is the means for centering the disc on the hub itself, for which said disc has a hole centrally wherein the neck of the hub is inserted, the disc being thus centered and positioned to finally carry out its coupling or fixation, for which are used several screws passing through a plate of the disc and a flange of the hub on the holes of which the screws are threaded.
Obviously, the use of several screws for fixing o coupling the disc, entails that the work, both for fixing and disassembly of the disc for its change, is slow and uncomfortable.